Capacitors are one type of component commonly used in the fabrication of integrated circuits, for example in DRAM circuitry. A capacitor is comprised of two conductive electrodes separated by a non-conducting dielectric region. As integrated circuitry density has increased, there is a continuing challenge to maintain sufficiently high storage capacitance despite typical decreasing capacitor area. The increase in density of integrated circuitry has typically resulted in greater reduction in the horizontal dimension of capacitors as compared to the vertical dimension. In many instances, the vertical dimension of capacitors has increased.
One manner of fabricating capacitors is to initially form an insulative material within which a capacitor storage node electrode is formed. For example, an array of capacitor electrode openings for individual capacitors may be fabricated in such insulative capacitor electrode-forming material, with an example insulative electrode-forming material being silicon dioxide doped with one or both of phosphorus and boron. The capacitor electrode openings may be formed by etching. It can be difficult to etch the capacitor electrode openings within the insulative material, particularly where the openings have high aspect ratio.
One manner of reducing such difficulty is to split the deposition and etch of such openings into two or more combinations of deposition and etch steps. For example, the material within which the capacitor electrode openings are to be formed can be deposited to an initial deposition thickness which is one half or less of the desired ultimate deposition thickness. Shallower capacitor electrode openings can then be etched to the underlying node location. Such openings are subsequently completely filled/plugged, and another material within which capacitor electrode openings will be formed is deposited over the material in which the first openings were formed and filled. Individual capacitor electrode openings are then formed through the overlying layer to the plugging material. Such can be repeated if desired. Regardless, the plugging material is at some point etched from the capacitor electrode openings to enable contact to be made to a node location on the substrate.
One common plugging material used in such instances is polysilicon. A native oxide can form on the outermost surfaces thereof that can be difficult to remove. Such oxide can be removed by etching prior to etching the polysilicon within the openings from the substrate. The native oxide etch is usually conducted using an HF wet etching solution. However, the material within which the capacitor electrode openings are usually formed is a doped silicon dioxide, such as borophosphosilicate glass or phosphosilicate glass. The HF will etch such material, thereby undesirably widening the capacitor electrode openings above the plugging material while removing the native oxide received thereover. Further and regardless, it can be difficult to remove the polysilicon plugging material from the openings. Example techniques in accordance with the above are described in U.S. Pat. Nos. 6,365,453 and 6,204,143.
Further and regardless, it is often desirable to etch away most if not all of the capacitor electrode-forming material after individual capacitor electrodes have been formed within the openings. Such enables outer sidewall surfaces of the electrodes to provide increased area and thereby increased capacitance for the capacitors being formed. However, the capacitor electrodes formed in deep openings are often correspondingly much taller than they are wide. This can lead to toppling of the capacitor electrodes, either during the etching to expose the outer sidewalls surfaces, during transport of the substrate, and/or during deposition of the capacitor dielectric layer or outer capacitor electrode layer. U.S. Pat. No. 6,667,502 teaches the provision of a brace or retaining structure intended to alleviate such toppling. Other aspects associated in the formation of a plurality of capacitors, some of which include bracing structures, are also disclosed and are:
U.S. Published Application No. 2005/0051822;
U.S. Published Application No. 2005/0054159;
U.S. Published Application No. 2005/0158949;
U.S. Published Application No. 2005/0287780;
U.S. Published Application No. 2006/0014344;
U.S. Published Application No. 2006/0051918;
U.S. Published Application No. 2006/0046420;
U.S. Published Application No. 2006/0121672;
U.S. Published Application No. 2006/0211211;
U.S. Published Application No. 2006/0263968;
U.S. Published Application No. 2006/0261440;
U.S. Published Application No. 2007/0032014;
U.S. Published Application No. 2006/0063344;
U.S. Published Application No. 2006/0063345.
Fabrication of capacitors in integrated circuitry such as memory circuitry may form an array of capacitors within a capacitor array area. Control or other circuitry area is often displaced from the capacitor array area, with the substrate including an intervening area between the capacitor array area and the control or other circuitry area. In some instances, a trench is formed in the intervening area between the capacitor array area and the other circuitry area. Such trench can be formed commensurate with the fabrication of the openings within the capacitor array area within which the isolated capacitor electrodes will be received.
While the invention was motivated in addressing the above-identified issues, it is no way so limited. The invention is only limited by the accompanying claims as literally worded, and in accordance with the doctrine of equivalence.